Question

Difference between sickle cell anemia and thalassemia

Answer 1

Explanation:

sickle-cell anemia:

a severe hereditary form of anaemia in which a mutated form of haemoglobin distorts the red blood cells into a crescent shape at low oxygen levels. It is commonest among those of African descent.

thalassemia :

Thalassemia is an inherited blood disorder characterised by less oxygen-carrying protein (haemoglobin) and fewer red blood cells in the body than normal

Answer 2

Sickle cell anemia, also known as sickle cell hemoglobin (HbSS) disease or homozygous SS disease, is an inherited autosomal recessive disorder resulting in qualitative mutation of the hemoglobin structure in red blood cells (RBCs). The mutation of normal hemoglobin A (α2ß2) to hemoglobin S (α2ß 6 Val2) is caused by the amino acid substitution of valine (GTG) for glutamic acid (GAG) on the sixth position of the ß chain. The sickling process occurs under deoxygenated conditions in which hemoglobin S polymerizes, forming aggregates called tactoids that give the resulting product a rigid structure. Nearly half of all patients with sickle cell anemia experience vaso-occulsive crisis (abdominal and joint/bone pain accompanied by fever) caused by masses of sickle cells trapped in the blood vessels due to decreased deformability of RBCs from tactoid formation.1 Sickle cell anemia has several characteristic laboratory findings. The peripheral blood smear results demonstrate normocytic, normochromic RBCs, the presence of nucleated RBCs (NRBCs), polychromasia, sickle cells, target cells, Howell-Jolly bodies, and Pappenheimer bodies. Neutrophilia and thrombocytosis may also be observed. The expected hemoglobin electrophoresis results in blood specimens from patients with sickle cell anemia show the following values: 80% sickle cell hemoglobin (HbSS), 1% to 20% hemoglobin F (HbF), 2% to 4.5% hemoglobin A2 (HbA2), and absence of hemoglobin A (HbA) if the patient has not recently received a transfusion.1

S/ß0 thalassemia results from the absence of ß-chain production that cause red blood cell (RBC) instability due to excess α chains, leading to abnormal erythropoiesis. S/ß0 thalassemia can be differentiated from sickle cell anemia based on RBC morphologic characteristics and hemoglobin electrophoresis results. S/ß0 thalassemia is characterized by microcytic, hypochromic RBCs, along with the presence of target cells and fewer sickle cells. The expected results of hemoglobin electrophoresis in patients with S/ß0 thalassemia are as follows: 75% to 90% sickle cell hemoglobin (HbSS), 5% to 20% hemoglobin F (HbF), 4% to 6% hemoglobin A2 (HbA2) (although in some cases, this cell count can be significantly elevated), and 0% hemoglobin A (HbA).1

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